During the past few decades in the electronics industry, Moore's Law has predicted that the number of transistors per unit area of a chip will double every 18 to 24 months, making the computing power of the chip ever more powerful. The number of input/output (I/O) counts of the chip has also increased to better take advantage of the exponentially growing computing power. The decreasing size of transistors often indicates that the increasing number of I/O counts (i.e., the decreasing I/O pitch) has to be realized in the same area, or proportionately even less.
Solder has been widely used to connect electronic components with each other and to connect electronic components to printed circuit boards (PCBs). However, as the I/O pitch decreases more and more, the size of the solder cannot decrease proportionally because of its intrinsic physical, chemical, and material properties.
One alternative to solder is the micro-interconnects, which comprise, among others, metal-based (e.g., copper) pillars or components. The metal-based pillars may achieve a finer I/O pitch and a better stand-off height, and have improved electrical and thermal properties. It is also possible that the metal-based pillars are conductive to lower manufacturing costs.
Accordingly, there is a need for an improved structure for interconnecting electronic components and for a method for making the improved interconnection structure.